Magnetically actuated switching contacts



Dec. 27, 1966 H. ANGERMAIER ETAL 3,294,944

MAGNETICALLY ACTUATED SWITCHING CONTACTS Filed Oct. 21, 1965 United States Patent 5 Claims. Cl. 200-166) This invention relates to magnetically actuated switching contacts and more particularly to spring contact sets of the sealed contact, or dry reed contact type.

This invention constitutes an improvement over the invention described in Angermaier application Serial No. 474,325, filed July 23, 1965, titled Magnetically Actuated Switching Contact Set. Reference may be had to that application for a more complete disclosure of the purposes and mode-s of operation of switches of this type.

The switching contact set of the type of which the invention relates employs fiat magnetizable spring contacts which serve both to carry electrical current and at the same time to conduct magnetic flux, for operation of the contacts. Moreover, as explained in the Angermaier application, such contacts preferably have at least one contact member provided, by slitting a portion of the length thereof, with at least two tongues of different width. In this system the wider tongue is employed for its magnetic eifects, while the narrower tongue is provided with an electrical contact material which extends beyond the plane defined by the flat surface of the wider tongue, and the narrower tongue is used for its electrical current conduction characteristics.

It is an object of the present invention to provide a magnetically actuate-d switching contact set of the type shown in the Angermaier application, but of the double throw type in which a center contact member is movable selectively into engagement with two opposite relatively fixed contact members. The invention employs a movable contact member having a pair of longitudinal slots dividing the member into a central relatively wide tongue, and two outer narrower tongues, the outer ends of this center switch element overlapping the outer ends of the respective relatively stationary switch elements. The narrower tongues of the movable contact element, as well as the opposite surfaces of the relatively stationary contact elements, are preferably provided with layers of electrical contact material extending beyond the planes of the respective contact elements, toward engagement with each other, over the area of that engagement.

The contact set of the present invention supplements the contact sets disclosed by the said Ange-rmaier application. With the present invention it is possible to form difierent variations of cutover or double throw switches. For example, with the present invention it is possible to form double throw switches utilizing coatings on the narrow contact tongues and the opposite stationary contacts, so that the double throw switch elements may be provided with double contacts, whose advantage is, of course, well known, particularly in the long distance communication field.

In accordance with a particularly preferred embodiment of the invention, the center tongue of the movable spring contact can be shorter than the outer tongues. With this construction, two additional advantages are obtained. On the one hand, the application of the layers of contact material is much simpler than previously, as the contact material can be plated over the entire spring contact, including the areas in which such material is not desired for operation of the constructed switch. However, during the operation of cutting out the tongues, the

superfluous areas of electrical contact mate-rial can be removed, with the portion of the spring contact on which it is fixed.

A second advantage of this particularly preferred embodiment provides for greater contact pressure of the electrical current conducting contact segments. This oc curs by reason of the fact that the extent of movement of the shorter middle tongue is necessarily less than of the outer longer tongues, since the outer ends of the longer tongues are at a greater distance from the pivot point of the movable contact member. With the center tongues moving into engagement with the fixed contact elements, and with the outer tongues required also to move into engagement with corresponding contact surfaces of the stationary contact elements, the greater movement required provides for greater contact pressure upon engagement.

A particular construction of the preferred embodiment of the invention might have the free ends of the outer tongues of the movable contact formed in such fashion as to curve around the leading edge of the middle tongue. The required form for this purpose could be easily shaped in the punching process. The advantages of this arrangement is that the contact points formed at the free ends of the outer tongues cause a twisting movement of the spring. Since torsion springs are known to be relatively chatterfree, the contact qualities are thereby improved.

In accordance with a further form of the invention, each outer tongue can be provided with contact material only on different surfaces thereof, for respective cooperation with opposite stationary contacts. With this construction it is possible to develop double throw switches which engage their contacts on both sides with especially high contact pressure, it the outer narrower tongues are both biased in the contact engagement direction. The result is that the spring path of the contact points is increased as compared with other constructions, until the middle tongue contacts the respective stationary contact, and of course, this causes the contact pressure to increase until that point is reached. A similar effect can of course be achieved through increasing the thickness of the layers of contact material.

In accordance with a further development of the invention, the spacing between the surfaces of the electrical contact material of the two fixed contacts may be the same as the distance between the opposite contact material surfaces of the center spring contact, so that the center contact is in simultaneous engagement with both fixed contacts in its rest or idle position. With such an arrangement a make-before-break double throw switch may readily be formed. With this construction, initial movement of the movable spring contact from its center position toward one fixed contact would decrease the contact pressure between the contact tongue and the opposite fixed contact and increase the pressure between the other narrow tongue and the fixed contact toward which the motion occurs. Upon suitable design of the elements, the spring forces and the contact layer thicknesses would permit removal of one of the two contact tongues from its adjacent fixed contact, in one energized position of the switch, while the other tongue is removed entirely from the other fixed contact in the opposite energized position of the switch.

The invention will now be more fully described in conjunction with preferred embodiments thereof shown in the accompanying drawing.

In the drawing:

FIG. 1 is a partial perspective view, partly in section, of a spring contact set constructed in accordance with the invention; and,

FIG. 2 is a similar perspective view showing the cen- 3 ter tongue of the movable contact as shorter than the outer tongues.

Referring first to FIG. 1, the fixed spring contacts 1 and 2 arearranged at opposite sides of movable spring contact 3. All of these contacts are of course magnetic material, so that a magnetic force acting in one direction or the other may cause motion of the movable contact into engagement with the appropriate fixed contact.

The movable contact 3 is divided by longitudinal slots into two outer narrow contact tongues 4 and 5, and a relatively wider central tongue 6. Both contact tongues 4 and 5 are coated adjacent their free ends with layers of electrical contact material 7, these layers being at opposite sides of the movable contact. Similar layers 8 are also formed on the fixed contacts 1 and 2.

As indicated in FIG. 1, the spacing between the opposite outer surfaces of the contact material 8 along the direction of center contact movement, is the same as the maximum thickness of the center spring contact 3, measured between the outer surfaces of its contact layers 7. As a result, the movable center contact engages both the fixed contacts in the position shown at FIG. 1, which is the idle or de-energized position of the switch. Upon the switch being subjected to magnetic force in one or the other direction of contact movement, the center tongue 6 is moved toward one of the outer fixed contacts 1 and 2. The contact pressure between the center spring contact and the fixed contact toward which it is moving is correspondingly increased, while at the same time the spring pressure with the other fixed contact is reduced. Then, by the time the center tongue 6 has engaged the fixed contact towards which it is moving, the outer tongue is completely disengaged from the other stationary contact.

It will be obvious that the contact set of FIG. 1 could be designed so that the center movable contact is in engagement with only one of the outer fixed contacts in the rest or idle position of the switch. This could be provided for by a mechanical construction biasing the movable contact into engagement with that stationary contact.

The construction of the spring contact set of FIG. 2 is very similar to that of FIG. 1, but it will be seen that the fixed contacts 9 and 10 are provided with center noses 13 opposite the center tongue 11 of the movable spring contact 12. As indicated hereinabove, the center tongue 11 may be shorter than the outer tongues 14, in the center movable contact, for purposes indicated above.

It will be evident that many minor changes could be made in the construction of the preferred embodiments of the invention described hereinabove. Accordingly, the invention is not to be considered limited to these embodiments, but rather only by the scope of the appended claims.

We claim:

1. A sealed electrical contact set including a center and a pair of outer spring contacts of magnetic material, each having end portions opposite each other, so that at least the center contact and one of the outer contacts engage upon switch actuation, both the center contact and said outer contacts being operable to carry both magnetic flux and electrical current,

the center contact having a pair of outer longitudinallyextending tongues at said one end portion defined by a pair of parallel slots extending inwardly of the contact from the end thereof, the outer tongues being more narrow than the center tongue,

and at least a pair of electrical contact layers, one of said pair being on one of the center contact and one of the outer contacts and positioned therebetween, the other of said layers being on one of the center contact and the other of the outer contacts and positioned therebetween, with said contact layers being positioned between the outer tongues of the center contact and the fixed contacts.

2. The apparatus of claim 1 in which said outer tongues of the center contact extend longitudinally beyond the center tongue thereof.

3. The apparatus of claim 1 in which said contact layers are positioned only between one of said outer contacts and one of said outer tongues and between the other outer contact and the other outer tongue, said outer contacts thereby being spaced from the opposite outer tongues.

The apparatus of claim 3 in which the spacing in the direction of movement of the center contact between the innermost surfaces of the two outer contacts, is the same as the greatest thickness of the center contact measured in the same direction, the center contact engaging both outer contacts in idle position, but the center tongue of the center contact being of less thickness than the spacing between the outer contacts in which it extends so that movement of the center contact to cause its center tongue to engage one of the outer contacts will cause disengagement between the other cuter contact and the outer tongue which normally engages it.

5. The apparatus of claim 4 in which said outer tongues of the center contact extend longitudinally beyond the center tongue thereof.

No references cited.

ROBERT K. SCI-IAEFER, Primary Examiner.

H. O. JONES, Assistant Examiner. 

1. A SEALED ELECTRICAL CONTACT SET INCLUDING A CENTER AND A PAIR OF OUTER SPRING CONTACTS OF MAGNETIC MATERIAL, EACH HAVING END PORTIONS OPPOSITE EACH OTHER, SO THAT AT LEAST THE CENTER CONTACT AND ONE OF THE OUTER CONTACTS ENGAGE UPON SWITCH ACTUATION, BOTH THE CENTER CONTACT AND SAID OUTER CONTACTS BEING OPERABLE TO CARRY BOTH MAGNETIC FLUX AND ELECTRICAL CURRENT, THE CENTER CONTACT HAVING A PAIR OF OUTER LONGITUDINALLYEXTENDING TONGUES AT SAID ONE END PORTION DEFINED BY A PAIR OF PARALLEL SLOTS EXTENDING INWARDLY OF THE CONTACT FROM THE END THEREOF, THE OUTER TONGUES BEING MORE NARROW THAN THE CENTER TONGUE, AND AT LEAST A PAIR OF ELECTRICAL LAYERS, ONE OF SAID PAIRS BEING ON ONE OF THE CENTER CONTACT AND ONE OF THE OUTER CONTACTS AND POSITIONED THEREBETWEEN, THE OTHER OF SAID LAYERS BEING ON ONE OF THE CETER CONTACT AND THE OTHER OF THE OUTER CONTACTS AND POSITIONED THEREBETWEEN, WITH SAID CONTACT LAYERS BEING POSITIONED BETWEEN THE OUTER TONGUES OF THE CENTER CONTACT AND THE FIXED CONTACTS. 